The district heating in Brno here in Czech Republic is in the process of converting from steam to hot water, mainly due to cost savings. Modern isolated hot water pipes loose a negligible ammount of heat in transfer while there was green grass growing on top of the old buried steam pipes even in winter.

That and the old textile industry that directly used steam no longer exists.

District heating with water is vastly more safe, I imagine that's why its used.

I remember my apartment in germany had a "Heat" meter on the water line, always wondered how that worked.

We have a calorimeter - it should count volume of hot water times the temperature difference. I heard it's not very precise.